Many industries require a warehousing system in which the product can be stored for a relatively short period of time and retrieved quickly, often in the same day in which the product enters the storage area. Examples of such industries include the dairy industry, the baking industry, and the soft drink industry. The standard practice utilized to store these types of palletized goods is to simply set the pallets around the plant or warehouse, either in a stacked or unstacked configuration. This method uses a great deal of warehouse space and requires a large labor force to maintain it. There are also significant problems with inventory control for this type of storage system. Orders are typically hand-picked from the floor, resulting in numerous errors.
Regarding transportation and retrieval of the stored products, conveyor systems are typically utilized to move the product between various areas of the warehouse. However, with this method, the product must be lifted onto the conveyor and pulled onto the floor when the product reaches its destination. This system is completely manual and requires a large and costly labor force.
Alternatively, there are systems to lift and transport products and/or pallets. For example, "stacker cranes" or automatic forklifts have been employed to follow on a track which is built into the warehouse. However, this type of device is limited in its depth or reach into a storage area to two pallets and is able to carry only one pallet at a time. Another transport device, called a "mole" system, allows access five to ten pallets deep into a storage area. This system incorporates a vehicle which is on an umbilical cord from a "stacker crane" and carries one pallet at a time. Although the "mole" allows for greater depth of reach in a storage area or lane, the cord limits its mobility. These two systems do not adequately accommodate an industry where a high volume of goods is moved in and out of the warehouse quickly, nor do they allow retrieval of quantities of goods smaller than a unit or pallet. Consequently, the warehouse space is not utilized efficiently.
Another example of a lift and transport system is a "walking beam" type storage system. In this system, goods are stored in single case lots. Goods rest on rails and are moved by rocker units which lift a case of goods, move forward approximately one case length, and place the case on the rest rail. Goods are "walked" through the warehouse in this manner. However, this system does not provide the versatility or efficiency that the present invention provides.
The present invention addresses the problems associated with the prior art devices and provides for a storage and retrieval system that is automated and particularly suited for a warehouse situation where goods are moved at a rapid rate.